The importance of the plants of the poppy family, for example Papaver and Eschscholtzia species, as a commercial source of medicinal opiates and related compounds is well known, and requires little introduction. The demand for these plant products is high.
Suitable agricultural land for commercial poppy growing is limited. Poppies need fertile, free draining soil which is not overly acidic. To reduce the build up of disease in commercially grown poppies, crops must be grown with at least a three year rotation (e.g. at least two to three different crops should be grown in the soil before poppies are grown again). There are other limitations such as topography and availability of water for irrigation. Presently in some areas, the crop area is probably close to the sustainable level—if higher yield of poppy products are desired then it will be necessary to either shorten the rotation or expand the area under cultivation to include marginal soil types. It is expected that employing these less than desirable practices will impact on factors such as yield and quality and produce undesirable related outcomes such as soil erosion and so on.
The alkaloid content in harvested poppy straw in Tasmania, for example, is generally in the range of 1.2% to 2.7% on a dry weight basis. The financial return to the growers is calculated on the basis of the alkaloid content. Thus, high alkaloid content plants mean that the poppy industry can compete with alternative crops which might potentially be grown in the same soils. High alkaloid content in the poppy crops makes the whole industry more competitive. Fewer hectares of crops would need to be grown to produce the same amount of alkaloid, and costs associated with harvesting, transport, storage, extraction and waste disposal would be reduced. Thus, high alkaloid producing poppies are highly desirable to growers, pharmaceutical companies and consumers of refined poppy products.
Conventional plant breeding has produced significant advances in poppy alkaloid contents over the last two decades. However, it appears that the amount of additional improvement possible through conventional breeding is limited.
Genetic transformation of poppies offers the opportunity to improve the alkaloid content of poppy crops and poppy straw. This could occur through a number of ways, including:                enhancement of activity of enzymes at “bottlenecks” in the alkaloid synthetic pathway;        blockage of undesirable “side reactions”; and        blockage of the synthetic pathway so that certain desirable alkaloids accumulate (e.g. thebaine, codeine, oripavine etc.).        
These types of improvement would thus allow the industry to continue to expand without increasing the area of crops grown. They would also introduce efficiencies throughout the production process.
As well as increasing the yield of desirable plant products, it is desirable to use related biotechnological procedures to introduce herbicide resistance into poppies. At present herbicide control of weeds in poppy crops is difficult and costly. Herbicides are not developed specifically for poppies and the spectrum of weed control of any one herbicide is not very wide. Thus programs of herbicides are applied involving a number of different products tank-mixed and applied in sequence. Development of a herbicide resistant poppy will enable the use of a herbicide with a wider margin of crop safety, and a wider weed spectrum than currently available. The cost of such weed control is expected to be significantly less than presently involved.
Genetic transformation may also be used to introduce other genes into poppies to impart commercially desirable properties, for example, resistance to disease, resistance to acid soil and resistance to insects and other pests.
Despite the desirability of such transformations, it has so far proved difficult to produce viable transgenic poppies. Attempts using conventional methods to introduce specific gene sequences encoding for certain properties and subsequent regeneration of transgenic poppies with predictable properties have thus far been mostly unsuccessful.
Thus there exists a need to develop methods for stably introducing genetic material into a plant which results in a plant which is viable and which possesses the desired traits.
It is an object of the present invention to overcome or ameliorate at least one or more of the abovementioned deficiencies in the prior art, or provide a useful alternative.